A program has been established to study different aspects of cell motility and chemotaxis in a number of developmental systems. These systems include 1) myoblast migration in the developing chick limb, 2) growth cone migration in Drosophila, 3) micromere migration in the sea urchin embryo, 4) chemotaxis and chemokinesis of amebae in the cellular slime mold, and 5) embryonic chick fibroblasts. A core facility has been developed for the quantitative analysis of cellular behavior and includes the most advanced instrumentation for motion analysis, image processing and fluorescence microscopy. A motility seminar will continue to serve the group both for research reports as well as a vehicle for remaining current in areas related to cell motility by seminars presented by visitors. The individual projects will examine the following developmental questions: 1) how myoblasts condense around the vasculature of the developing limb and how micromeres interact with matrix material during migration in the sea urchin, 2) how mutant neurons with defective nerve-specific cAMP phosphodiesterase and adenylate cyclase activities behave in culture, and what molecular or cytoskeletal processes are defective in a mutation, shits, which disrupts adhesion and growth cone activity in Drosophila, 3) how antisera to the myosin light chain kinase or the tropomyosin isoforms affect cell behavior when microinjected into embryonic fibroblasts, and 4) finally, how slime mold amebae assess temporal and spatial gradients of chemoattractant. In addition, we will continue to develop software for the motion analysis machine which will allow us to monitor amebae in three dimensions and calculate both motion and morphometric parameters. This program project is developed around the central theme of the regulation of cell motility in development and obtains its vitality and focus from the scientific interactions of the participants and the synergism which results from the different expertise of the individual investigators.